The synergy of working memory and inhibitory control: behavioral, pharmacological and neural functional evidences

Concomitant deficits in working memory and behavioral inhibition in several psychiatric disorders like attention-deficit/hyperactivity disorder, addiction or mania, suggest that common brain mechanisms may underlie their etiologies. Based on the theoretical assumption that a continuum exists between health and mental disorders, we explored the relationship between working memory and inhibition in healthy individuals, through spontaneous inter individual differences in behavior, and tested the hypothesis of a functional link through the fronto-striatal dopaminergic system. Rats were classified into three groups, showing good, intermediate and poor working memory and were compared for their inhibitory abilities. These two functions were simultaneously modulated by a dose-effect of d-amphetamine and in situ hybridization was used to quantify dopaminergic receptor (RD1) mRNAs in prefrontal cortex and striatal areas. A functional relationship between working memory and inhibition abilities was revealed. Both functions were similarly modulated by d-amphetamine according to an inverted-U shaped relationship and depending on initial individual performances. D-amphetamine selectively improved working memory and inhibition of poor and intermediate performers at low doses whereas it impaired both processes in good performers at a higher dose. D1 receptors were less expressed in prelimbic, infralimbic and anterior cingulate cortices of good compared to intermediate and poor performers, whereas no difference was observed between groups in striatal areas. The synergy of working memory and inhibitory abilities, observed in both healthy and psychiatric populations, may originate from endogenous variability in dopaminergic prefrontal cortex activity. Such findings confirm the validity of a dimensional approach, based on the concept of continuity between health and mental disorders for identifying endophenotypes of mental disorders.     

Bias in self-motion perceived speed can enhance episodic memory

Prior experiences of a stimulus facilitate reprocessing of that stimulus on a subsequent occasion. This relative ease and speed with which information is processed is defined as fluency and can constitute a basis for memory judgment. Fluency can also be manipulated on line by perceptual bias (e.g., levels of noise), leading to an increase in recognition for items processed more fluently (e.g., items with less noise). Previous experiments using Remember-Know paradigm have shown an impact of perceptual fluency only on familiarity and not on recollection. Recent episodic memory models have postulated a strong link between episodic memory and spatial processes, especially with egocentric updating (Gomez et al. in Acta Psychol 132(3):221-227, 2009). The present experiment was conducted to determine whether self-motion fluency affects recognition performance and particularly has an impact on "Remember" responses. Thirty participants learned a 4-min path movie and then had to recognize among short paths if they were part of the learned path, followed by a Remember-Know procedure for recognized items. Self-motion fluency was manipulated with the presence of nimble acceleration applied on a small part of the recognition paths. Results show that the presence of a self-motion fluency increases significantly the proportion of remember responses solely on learned paths. This study spotlights for the first time a specific fluency effect on recollection and indicates an implication of egocentric-updating processing in episodic memory retrieval.     

Even simple forms of social learning rely on intention attribution in marmoset monkeys (Callithrix jacchus)

Intention attribution guides the cognitively most demanding forms of social learning, such as imitation, thereby scaffolding cumulative cultural evolution. However, it is not thought to be necessary for more basic forms of social learning. Here we present evidence that in marmoset monkeys (Callithrix jacchus) even most basic forms of social learning such as enhancement depend on intention attribution. Marmosets perceived the behavior of a conspecific and a conspecific-like robot, but not that of a moving black box, as goal directed. Their subsequent choice behavior was shaped by social facilitation and stimulus enhancement, that is, by very simple forms of social learning, but only when exposed to the conspecific and robot, which they previously had perceived as intentional agents. We discuss the implications of this finding for contemporary debates about social learning, including emulation learning and ghost control studies, the necessity of goal-directed copying for cumulative cultural evolution, and the limits of current classification systems of social learning for the evolution of social and asocial learning.     

Development of a Facebook Addiction Scale

The Bergen Facebook Addiction Scale (BFAS), initially a pool of 18 items, three reflecting each of the six core elements of addiction (salience, mood modification, tolerance, withdrawal, conflict, and relapse), was constructed and administered to 423 students together with several other standardized self-report scales (Addictive Tendencies Scale, Online Sociability Scale, Facebook Attitude Scale, NEO-FFI, BIS/BAS scales, and Sleep questions). That item within each of the six addiction elements with the highest corrected item-total correlation was retained in the final scale. The factor structure of the scale was good (RMSEA = .046, CFI = .99) and coefficient alpha was .83. The 3-week test-retest reliability coefficient was .82. The scores converged with scores for other scales of Facebook activity. Also, they were positively related to Neuroticism and Extraversion, and negatively related to Conscientiousness. High scores on the new scale were associated with delayed bedtimes and rising times.     

Development of a work addiction scale

Andreassen, C. S., Griffiths, M. D., Hetland, J. & Pallesen, S. (2012). Development of a work addiction scale. Scandinavian Journal of Psychology 53, 265–272. Research into excessive work has gained increasing attention over the last 20 years. Terms such as “workaholism,”“work addiction” and “excessive work” have been used interchangeably. Given the increase in empirical research, this study presents the development of the Bergen Work Addiction Scale (BWAS), a new psychometrically validated scale for the assessment of work addiction. A pool of 14 items, with two reflecting each of seven core elements of addiction (i.e., salience, mood modification, tolerance, withdrawal, conflict, relapse, and problems) was initially constructed. The items were then administered to two samples, one recruited by a web survey following a television broadcast about workaholism (n = 11,769) and one comprising participants in the second wave of a longitudinal internet‐based survey about working life (n = 368). The items with the highest corrected item‐total correlation from within each of the seven addiction elements were retained in the final scale. The assumed one‐factor solution of the refined seven‐item scale was acceptable (root mean square error of approximation = 0.077, Comparative Fit Index = 0.96, Tucker‐Lewis Index = 0.95) and the internal reliability of the two samples were 0.84 and 0.80, respectively. The scores of the BWAS converged with scores on other workaholism scales, except for a Work Enjoyment subscale. A suggested cut‐off for categorization of workaholics showed good discriminative ability in terms of working hours, leadership position, and subjective health complaints. It is concluded that the BWAS has good psychometric properties.     

“Don't let the group down”: Facets of instrumentality moderate the motivating effects of groups in a field experiment

The motivating effects of group work as compared with individual work are not restricted to the research laboratory but have recently been documented in existing groups performing meaningful tasks. Freestyle swimmers at the 2008 Olympics were shown to swim faster in relay groups than in the individual competitions when their contribution was highly instrumental for the relay group (i.e., indispensable) because of their serial position in the group. The present study replicated and extended this work, aggregating a larger sample from major sports events (N = 199 freestyle swimmers) that also allowed for a competitive test between the instrumentality approach and explanations based on differences in the starting procedures of relay and individual competitions. Consistent with expectancy value models of effort expenditure in groups, swimmers were faster in the relay groups as compared with individual competitions only when (i) a swimmer's performance was highly instrumental for the group's performance (i.e., later serial position in the relay) and (ii) the group's performance was highly instrumental for a positive group outcome (i.e., the relay group had a good chance of winning a medal). The data were not consistent with an explanation of performance differences merely as a result of different starting procedures. Copyright © 2012 John Wiley & Sons, Ltd.     

Performance on auditory and visual temporal information processing is related to psychometric intelligence

The present study investigated the relationship between psychometric intelligence and temporal resolution power (TRP) as simultaneously assessed by auditory and visual psychophysical timing tasks. In addition, three different theoretical models of the functional relationship between TRP and psychometric intelligence as assessed by means of the Adaptive Matrices Test (AMT) were developed. To test the validity of these models, structural equation modeling was applied. Empirical data supported a hierarchical model that assumed auditory and visual modality-specific temporal processing at a first level and amodal temporal processing at a second level. This second-order latent variable was substantially correlated with psychometric intelligence. Therefore, the relationship between psychometric intelligence and psychophysical timing performance can be explained best by a hierarchical model of temporal information processing.